Gas-operated self-loading firearm



Feb. 27, 1945. H. L. cRocKE-rr GAS-OPERATED SELF-LOADING FIREAHM 2 Sheets-Sheet 1 Filed Jan. 26, 1944 vf r,... s, www nom F erV u` H M, w i

Feb. 27, 1945. H, QROCKETT 2,370,233

GAS OPERATED SELF- LUADING FIREARH Filed Jan. 26, 1944 2 Sheets-Sheet 2 maa,

Patented Feb. 27, 1945 2,370,233 GAS-OPERATED SELF-LOADING FIREABM Harry L. Crockett, New Haven, Conn., asslgnor to Western Cartridge Company,

New Haven,

Conn.. a corporation of Delaware Application January 26. 1844, Serial No. 519,741

BCialms.

The present invention relates to improvements in self-loading firearms and relates more particularly to improvements in gas-operated selfloading firearms, i. e., nrearms of the type wherein gas pressure from the bore of the barrel actuates a piston which, in turn, actuates the breechbolt and associated features of the firearm to effect the extraction and ejection of the just-fired cartridge, preparatory to the automatic reloading of the rearm with a fresh cartridge.

One of the objects of the present invention is to provide a superior gas-operated self-loading firearm having a stationary guide-rod and an action-slide guided thereby and in which the construction and arrangement of parts is such that the same means asis employed for mounting the said guide-rod may be utilized to retain the stock in place.

Another object of the present invention is to provide a gas-operated self-loading rearm with superior means whereby a guide-rod, stock and trigger-plate may be releasably secured in place by common mea With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, tain modes of carrying out the tion are shown for illustrative purposes:

Fig. l is a broken view of the central portion of a gas-operated self-loading firearm embodying the present invention and showing the same in in which cerside elevation, save for the stock which is shown in vertical central-longitudinal section;

Fig. 2 is a broken view in vertical central-longitudinal section of the elements of the rearm which are located adjacent the cylinder-lug of the barrel and the forward portion of the triggerplate unit;

Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 1;

Fig. 4 is a broken underside view of a portion of the firearm-structure with the stock and the 45 trigger-plate unit removed:

Fig. 5 is a top or plan view of the trigger-plate unit, detached;

Fig. 6 is a view thereof in side elevation:

Fig. 7 is a view in side elevation of the action- 60 slide-detached;

Fig. 8 is a transverse sectional view taken on the line 8-8 of Fig. 7;

Fig. 9 is a top or plan view of the guide-rod. detached;

Fig. 10 is a View thereof in side elevation;

Fig. 11 is a perspective view of the guide-rod;

Fig. 12 is a perspective view of the attachingstud, detached; and

Fig. 13 is a broken underside view of the forward portion of the receiver.

The particular gas-operated self-loading rearm-structure chosen for illustration in' the accompanying drawings to make clear one form of the present invention, comprises, as its main elements, a receiver il. a barrel unit Il. an action-slide i2 and a stock I8.

The forward end of the receiver It has rigidly connected thereto in any suitable manner, the rear end of the aforesaid barrel I2. The said receiver is formed interiorly with a mechanismreceiving chamber 2li accommodating varioi features of the dream-mechanism. which latter do not require detailed description herein, other than to note that the said mechanism includes a breech-bolt 2| having both reciprocating and oscillatory movement in the upper portion of the .chamber in a manner broadly similar to the breech-bolt of the well-known Garand military As is shown in Figs. 1, 2 and 3, the stock I3 is suitably recessed to accommodate portions of the receiver I i, barrel it, trigger-plate unit I'I and associated features of the firearm.

present inven- At a point slightly forwardly of its rear end,

the barrel it is formed with an integral depending cylinder-lug 22 having a rearwardly-opening piston-chamber 23 therein, arranged with its extending in substantial parallelism with the longitudinal aids of the barrel I 6. Intersecting and leading forwardly and upwardly from the rear face of the front wall of the said piston-chamber is an inclined gas-passage 24 communicating at its forward upper end with the bore 25 of the barrel It, so as to conduct gas under pressure from the said bore to the piston-chamber 23 for the actuation of a pistoni in a manner as will hereinafter appear. l

Mounted for reciprocation in the piston-chamber 22 of the cylinder-lug 22, is the relativelysmall-diametered forward portion 26 of a cupshaped piston generally designated by the reference character 21. Located rearwardly of the rear face oi' the cylinder-lug 22. is the relatively-largediametered head 28 of the said piston 21. The said cup-shaped piston is formed with a rearwardly-opening cylindrically-contoured socket 29 receiving with a sliding t, the stem lll of a guiderod 3l.. The said guide-rod extends beneath the barrel li in substantial parallelism with the bore It, a trigger-plate 25 thereof and in substantially-coaxial arrangement with respect to the central-longitudinal axis of the piston 21.

At its rear end, the guide-rod Il is formed with an integral eye-like terminal or head 22 having a vertical passage 33 extending therethrough and having its lower face substantially flush with the under face of the guide-rod 2l proper but having its upper face located in a plane below the upper surface of the said guiderod proper.

'I'he upper portion of the terminal 32 of the guide-rod 3| is accommodated in a shallow downwardly-opening recess 8l formed in the under face of the forward portion of the receiver I while the lower portion thereof is accommodated in a longitudinal groove 35a intersecting the said recess 34. The said recess 3l has its lateral boundaries shaped to conform to the lateral boundaries of the eye-like terminal 32 of the guide-rod 3|, so that the rear wall of the said recess forms a seat for the rear face of the upper portion of the said terminal 32.

Axially in line with the passage 22 in the terminal 32 of the guide-rod 3i, the receiver I5 is formed with a. vertical threaded socket 35 receiving the threaded stem 25 of an attachingstud 31. The stem 35 Just referred to extends upwardly from the said attaching-stud. through the passage 33 in the terminal 32 of the guiderod 3|, and thence into threaded engagement with the socket 35 in the forward portion of the receiver I5, as is particularly well shown in Figs. 2 and 3. When screwed home, the said attaching-stud 31 serves to clamp the terminal 92 oi' the guide-rod 2| firmly in place in the recess 34 in the receiver I5, so that the said guide-rod is firmly held against displacement.

In its lower portion, the attaching-stud 21 formed with a downwardly-opening threaded socket 38 receiving the threaded shank of an attaching-screw 29. The lower portion of the attaching-stud 21 is also formed with a diametrical kerf III by means of which the attaching-stud may be rotated. The attaching-screw 39 has the head at its lower end accommodated in a downwardly-opening recess or counterbore II formed in a tang I2 located at the forward lower corner of the trigger-plate unit l1. The threaded stem of the attaching-screw 39 extends upwardly through the tang 42 and through the adjacent portion of the stock I 9 and thence into the socket 3B in the attaching-stud 31. 'I'he lower portion of the attaching-stud 31 is accommodated in an upwardly-opening clearancerecess I3 formed in the stock I9, while the tang 42 just referred to is accommodated in a downwardly-opening recess M formed in the under face of the said stock.

As thus constructed and arranged, the attaching-stud v31 not only serves to hold the rear end of the guide-rod 3l in place but, with the aid of the attaching-screw 39, also serves to hold the forward portion of the trigger-plate unit I1 and the stock I9 in place.

The forward `rportion of the trigger-plate unit I1 before referred to. is relatively wide as compared to the rear portion thereof, and is provided with a vertical magazine-receiving passage I5 into which a suitable box-magazine may be installed from the underside of the rearm structure. The lower rear portion of the triggerplate unit I1 is formed with a depending looplike trigger-guard I6 in which the finger-piece 41 of a suitable trigger is adapted to move. The

rear portion of the trigger-plate unit I1 also carries a hammer 4B controlled by complemental sears 49 and 49a which are, in turn, controlled by the finger-piece 41 before referred to.

At its extreme rear end, the trigger-plate unit I1 is formed with a vertically-apertured tang 50 through which extends a vertical attaching-screw 5I extending upwardly through thel stock I9 and threadedly engaged with the rear part of the receiver I5.

The action-slide IB before referred to is formed at its forward end with a front-head 52, from the upper right-hand portion of which rearwardly extends an integral side-bar 53, which latter terminates at its rear end in a rear-head 54. The rear-head 5l is formed with an outwardly-extending operating-handle 55 by means of which the firearm may be cocked and otherwise prepared for discharge. In its inner face, the rearhead 54 is formed with a cam-recess 55 into which ts a lug 51 laterally offsetting from the forward end of the breech-bolt 2|. The coaction of the lug 51 and the surfaces of the cam-recess 56, l

serves to operatively interconnect the actionslide IB and the breech-bolt 2| in a manner broadly similar to the connection employed in the well-known Garand military rifle.

The front-head 52 of the action-slide I8 is formed substantially centrally with a longitudinally-extending hearing-passage 58, which is proportioned to receive with a free sliding fit. the main or intermediate portion of the guide-rod 3l. Normally engaged with the front face of the front-head 52 is the rear face of the cupshasped piston 21, which latter functions to drive the action-slide rearwardly to effect the operation of the breech-bolt 2i, in a manner as will hereinafter appear.

For the purpose of yieldingly urging the actionslide IB forwardly into its foremost position and hence also urging the breech-bolt 2| into its breech-closing position, a helical breech-closing spring 59 is employed. The forward portion of the said breech-closing spring 59 encircles a breech-closing plunger Gil and has its forward end seated against the rear face of an integral collar 5I adjacent the forward end of the said plunger. Extending forwardly from the collar 6I is an integral stem 52 releasably fitting into a. rearwardly-opening socket 53 formed in the rear face of the front-head 52 of the action-slide I8.

The rear portion of the breech-closing spring 59 and the rear portion of the plunger BI) extend within a forwardly-opening spring-chamber 6d formed in the lower portion of the right-hand wall of the receiver I5. The rear end of the breechclosing spring 59 thrusts against the rear Wall of the spring-chamber B4 and thereby exerts a constant-but-yielding effort to maintain the actionslide I8 in its full forward position.

Normally, the breech-closing spring 59 acting through the breech-closing-plunger B0, maintains the forward face of the front-head 52 of the ax:- tion-slide I8 in engagement with the rear face of the piston 21 and, in turn. maintains the forward end of the said piston against the front wall of the piston-@amber 23, as is especially well shown in Fig. 2.

When the firearm is discharged, gas under pressure will pass downwardly and rearwardly from the bore 25 of the barrel IB and impinge against the forward end of the piston 21. Under these conditions, the piston 21 will be moved violently rearwardly until the rear face of the iront wall of the socket 2l therein engages with The movement imparted to the piston 21 as just described, will cause the piston to, in turn. impart rapid movement to the action-slide il, which latter will be thrown rearwardly against the tension of the breech-closing spring l0.

During its rearward travel as above described. the action-slide I8 will, through the intermediary of its cam-recess IB and the lug l1 of the breechbolt 2|, efl'ect the unlocking and retraction oi' the said breech-bolt. This movement will, in the usual manner of nrearms, eiiect the extraction and ejection of the just-tired cartridge. Following the completion of the actions Just above described. the breech-closing spring will act to again restore the parts to the positions in which they are shown in Figs. 1, 2 and 4.

During the reciprocating movement of the action-slide I8, the forward portion thereof will be guided by the sliding of the surface of the bearing-passage 58 in the iront-head 82 upon the guide-rod 3 I. 'I'he rear portion of the action-slide may be guided in any desired manner such, for

instance, as by means on the receiver Il.

When it is desired to separate the elements oi' the rearm for purposes of inspection, repair or cleaning, the trigger-plate unit il and the stock I9 may be removed by llrst removing the attaching-screws 39 and 5i. Following the removal oi the two elements Just mentioned. the guide-rod Il, action-slide il and associated elements stili remain operatively connected to the firearmstructure for test. if desired. When, however, it is desired to dismount the guide-rod 3| and the action-slide I8, the attaching-stud 81 may be unscrewed and removed, whereupon the rear end of the guide-rod 3| may be slightly depressed t0 disengage its eye-like terminal 32 from the rear wail o! the recess 34 in the receiver i6. Under these conditions, the guide-rod 3l may now be removed by moving the same rearwardly in the groove 34a, so as to slide its forward portion out or the piston 21 and out of the iront-head 52 of the action-slide i8.

Ihe breech-closing spring 59 and the breechclosing plunger 6B may be removed by rst moving the said breech-closing plunger sumciently rearward to disengage its Stern 62 from the socket t3 in the front-head 52 and then deilecting the forward end of the said guide-rod laterally beyond the side wall of the said front-head l2. Under these conditions, the breech-closing spring 59 and the breech-closing plunger l0 may be withdrawn forwardly from the spring-chamber Il in the receiver and totally disconnect it from the rearm-structure.

The action-slide i8 as thus freed from connection with the guide-rod 3i and the spring-closing plunger Sli, may now itself be dismounted from the remainder of the firearm-structure.

The invention may be carried out in other specic ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be vconsidered in all respects as illustrative and not restrictive. and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. A gas-operated self-loading ilrearm-structure, including in combination: a receiver-unit; a breech-bolt movable in the said receiver-unit; a barrel projecting forwardly from the said receiver-unit: a cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communicating with the bore o! the said barrel: a piston reciprocating in the piston-chamber o! the said cylinder; a guide-rod formed separately from and arranged substantially coaxially with respect to the said piston and extending rearwardly from a point adjacent the same, the said guide-rod having an apertured rear end adjacent the said receiver-unit; an action-slide operatively interconnecting the said breech-bolt and the said piston and having a portion sliding on the said guide-rod; first attaching-means having a portion extending through the apertured rear end oi' the said guide-rod and coupling the same to the said receiver-unit; a trigger-plate unit adjacent the said receiver-unit and having a portion located in a plane below the said guide-rod; and second attaching-means extending through and releasably attaching the said trigger-plate unit to the said first attachingmeans.

2. A gas-operated self-loading firearm-structure, including in combination: a receiver-unit; a breech-bolt movable in the said receiver-unit; a barrel projecting forwardly from the said reoeiver-unit; a. cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communicating with the bore of the said barrel; a piston reciprocating in the piston-chamber of the said cylinder; a guide-rod formed separately from and arranged substantially coaxially with respect to the said piston and extending rearwardly from a point adjacent the same, the said guide-rod having an apertured rear end adjacent the said receiver-unit; an action-slide operatively interconnecting the said breech-bolt and the said piston and having a portion sliding on the said guide-rod: first attaching-means having a portion extending through the apertured rear end of the said guide-rod and coupling the same to the said receiver-unit: a trigger-plate unit adjacent the said receiver-unit and having a portion located in a plane below the said guide-rod;

" a stock having a portion covering parts of both the said guide-rod and the said trigger-plate unit; and second attaching-means extending through and releasably attaching the said trigger-plate unit and the said stock to the said rst attachingmeans.

3. A gas-operated self-loading firearm-structure, including in combination: a receiver-unit: a breech-bolt movable in the said receiver-unit; a barrel projecting forwardly from the said receiver-unit: a cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communicating with the bore of the said barrel: a cup-shaped piston reciprocating in the pistonchamber oi the said cylinder and formed with a rearwardly-opening socket: a. guide-rod formed separately from and arranged substantially coaxiallywith respect to the said cup-shaped niston and having a forward portion tting into the socket therein, the said guide-rod having an apertured rear end adjacent the said receiver-unit; an action-slide operatively interconnecting the said breech-bolt and the said piston and having o. portion sliding on the said guide-rod; first attaching-means having a portion extending through the apertured rear end of the said guiderod and coupling the same to the said receiverunit; a trigger-plate unit adjacent the said reoeiver-unit and having a portion located in a plane below the said guide-rod; and second attaching-means extending through and releasably attaching the said trigger-plate unit tothe said rst attaching-means.

4. A gas-operated self-loading firearm-structure, including in combination: a receiver-unit; a breech-bolt movable in the said receiver-unit: a barrel projecting forwardly from the said receiver-unit; a cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communicating with the bore of the said barrel: a cup-shaped piston reciprocating in the pistonchamber of the said cylinder and formed with a rearwardly-opening socket; a, guide-rod formed separately from and arranged substantially coaxially with respect to the said cup-shaped piston and having a forward portion fitting into the socket therein, the said guide-rod having an apertured rear end adjacent the said receiver-unit; an action-slide operatively interconnecting the said breech-bolt and the said piston and having a, portion sliding on the said guide-rod; first attaching-means having a portion extending through the apertured rear end of the said guiderod and coupling the same to the said receiverunit; a trigger-plate unit adjacent the said receiver-unit and having a portion located in a plane below the said guide-rod; a stock having a portion covering parts of both the said guide-rod and the said trigger-plate unit: and second attaching-means extending through and releasably attaching the said trigger-plate unit and the said stock to the said first attaching-means.

5. A gas-operated self-loading firearm-struc ture, including in combination: a receiver-unit formed adjacent its forward end with a downwardly-opening threaded socket; a breech-bolt movable in the said receiver-unit; a barrel projecting forwardly from the said receiver-unit; a cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communieating with the bore of the said barrel; a piston reciprocating in the piston-chamber of the said cylinder; a guide-rod formed separately from and arranged substantially coaxially with respect to the said piston and extending rearwardly from a point adjacent the same, the said guide-rod having an apertured rear end adjacent the threaded socket in the said receiver-unit; an action-slide operatively interconnecting the said breech-bolt and the said piston and having a portion sliding on the said guide-rod; an attaching-stud having a threaded stem extending upwardly through the apertured rear end of the said guide-rod and into the threaded socket in the said receiver-unit to couple the said guide-rod to the said receiverunit; a trigger-plate unit adjacent the said receiver-unit and having a portion located in a plane below the said guide-rod and the said attaching-stud; and an attaching-screw extending upwardly through the said trigger-plate unit into threaded engagement with the said attachingstud to releasably connect the forward portion of the said trigger-plate unit to the said attachingstud.

6. A gas-operated self-loading firearm-structure, including in combination: a receiver-unit formed adjacent its forward end with a downwardly-opening threaded socket; a breech-bolt movable in the said receiver-unit; a barrel projecting forwardly from the said receiver-unit; a cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communieating with the bore of the said barrel; a piston reciprocating in the piston-chamber of the said cylinder; a guide-rod formed separately from and arranged substantially coaxially with respect to the said piston and extending rearwardly from a point adjacent the same, the said guide-rod having an apertured rear end adjacent the threaded socket in the said receiver-unit; an

- action-slide operatively interconnecting the said breech-bolt and the said piston and having a portion sliding on the said guide-rod; an attachingstud having a threaded stem extending upwardly through the apertured rear end of the said guiderod and into the threaded socket in the said receiver-unit to couple the said guide-rod to the said receiver-unit: a triggerplate unit adjacent the said receiver-unit and having a portion located in a plane beow the said guide-rod and the said attaching-stud; a stock extending intermediate the forward portion of the said triggerplate unit and the said receiver-unit; and an attaching-screw extending upwardly through the said trigger-plate unit and the said stock into threaded engagement with the said attachingstud to releasably connect the said trigger-plate unit and the said stock to the said attaching-stud.

7. A gas-operated self-loading frearmstruc ture, including in combinar-ion: a receiver-unit formed adjacent its forward end with i downwardly-opening threaded socket; a breech-bolt movable in the said rcceivehunit; a barrel projecting forwardly from the said receiver-unit; a cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communi eating with the bore of the said barrel; a cupshaped piston reciprocating in the piston-chamber of the said cylinder and formed with a rearwardly-opening socket; a guide-rod formed separately from and arranged substantially coaxially with respect to the said cup-shaped piston and having a forward portion fitting into the socket therein, the said guide-rod having an apertured rear end adjacent the threaded socket in the said receiver-unit; an action-slide operatively interconnecting lche said breech-bolt and the said piston and having a portion sliding on the said guide-rod; an attaching-stud having a threaded stem extending upwardly through the apertured rear end of the said guide-rod and into the threaded socket in the said receiver-unit to couple the said guide-rod to the said receiver-unit; a trigger-plate unit adjacent the said receiver-unit and having a portion located in a plane below the said guide-rod and the said attaching-stud; and an attaching-screw extending upwardly through the said trigger-plate unit into threaded engagement with the said attaching-stud to releasably connect the forward portion of the said trigger-plate unit to the said attaching-stud.

B. A gas-operated self-loading firearm-structure. including in combination: a receiver-unit formed adjacent its forward end with a downwardly-opening threaded socket; a breech-bolt movable in the said receiver-unit; a barrel projecting forwardly from the said receiver-unit; a cylinder adjacent the said barrel and having a rearwardly-opening piston-chamber communieating with the bore of the said barrel; a cupshaped piston reciprocating in the piston-chamber of the said cylinder and formed with a rearwardly-opening socket; a guide-rod formed separately from and arranged substantially coaxially with respect to the said cup-shaped piston and having a forward portion iitting into the socket therein, the said guide-rod having an apertured rear end adjacent the threaded socket in the said receiver-unit; an action-slide operatively interconnecting the said breech-bolt and the said piston and having a portion sliding on the said guide-rod; an attaching-stud having a threaded stem extending upwardly through the apertured rear end of the said guide-rod and into the threaded socket in the said receiver-unit to couple 5 the said guide-rod to the said receiver-unit; a trigger-plate unit adjacent the said receiver-unit and having a portion located in a plane below the said guide-rod and the said attaching-stud; a

' said attaching-stud to releasably connect the said trigger-plate unit and the said stock to the said attaching-stud.

HARRY L. CROCKE'IT. 

